ArduCopter 2.5 released!

Version 2.5 of the ArduCopter code is now available in the AP Mission Planner and in the downloads area!



  1. The first ArduCopter code release optimized for the APM 2.  Leans and drift should be much reduced or even eliminated for most users.  This was accomplished through a number of core improvements to the DCM implementation by Tridge like this one and this one.
  2. Loiter and waypoint following should be improved due to a D term bug fix, some tuning and the improved DCM performance mentioned above.
  3. On start-up, the yaw heading is updated with first successful mag read (so you should no longer see the slow rotation from north to your actual heading).
  4. Increased output rate to ESCs to 490hz.  This update rate is also user selectable using the new RC_SPEED parameter.
  5. hexa copter stability patch bug fix (should resolve slight flattening when pitching forward and accelerating very rapidly).
  6. improved baro filtering
  7. fix to dataflash logging of Mag heading
  8. addition of H1 swash plate type and bug fix for proactive yaw compensation for collective pitch changes for TradHelis.



The default PIDs are optimized for a 3DR/Jdrones quad with 850 motors and 10" props. If you're using more powerful motors/props, start by turning down Rate Roll P in 25% steps.

While some testers have reported very good flights with the default PIDs, some have reported that this release is a little "sharper" due to the DCM improvements and have found they needed to:

     reduce stabilize P by 10% (i.e. 4.5 -> 4.2)

     reduce stabilize D by 30% (i.e. 0.15 -> 0.10)

     increase rate D from 0 to 0.001

Tuning loiter can be tricky.  Refer to the discussions which will appear below for more community feedback on what parameters work best.


Please post your feedback in this discussion.  For enhancement requests  and bug report, please add them to the arducopter issues list.  When possible please include logs (tlog and/or dataflash) and tell us whether you're using APM1 or APM2 and what version of the software you're using (presumably 2.5 but tell us anyway!).


Thanks for this release go to the developers (both in the core team but also those who have provided bug fixes through the issues list) and also the community members who participated in the previous release thread and provided some great detailed information in the form of issue reports and logs which allowed us to nail some bugs!


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  • Another solution could be making a y cable from the pdb and plugging in charged battery before unplugging discharged one. As long as the batteries were the same in mah then it should be ok or would the few seccond connection to a discharged battery drain the charged one?
  • Are there any instructions on installing this on the mtk gps?

    Or can I just follow the instructions for adding a battery?
  • Regarding the simple and super simple modes. I have been using what I guess is simple mode because I'm just using iton the ch7 switch. I never fly to close to myself so haven't run into the problems described earlier. Now after reading the wiki about it, I don't think the instructions are clear. Simple talks about flying the compass and pushing forward take the copter north but I think who wrote that might have meant relative north or in other words in the direction the copter was facing. Super simple I've never tried but I'm not sure what the difference would be. In both cases wouldn't pulling the stick back bring it home, assuming you haven't walked away from your launch point. Is the difference in ss mode that you can turn around and pulling the stick towards you would bring it back even if you had turned your body 90 degrees? Definitely seems more intuitive if that is the was ss mode works. Maybe in the wiki there could be some graphic to show the differences.
  • I need some help on tuning my hexa.  I built this hexa for AP purposes.

    I'll try to explain what I want out of my copter.



    Alt-hold is working, the copter stays within 1 meter or so.

    The problem is that it reacts too aggressively.  I would like the throttle to be increased in a soft way to maintain altitude.

    Which parameters do I need to adjust up or down to get this kind of effect?



    When there is some wind, the copter starts to drift immediately.  When it's away from the point where loiter was engaged, the copter reacts very aggressively.  The copter also tends to loiter in circles.

    The same here, which parameters do I need to tune up or down to get better results.



    It's flying stable most of the time.  Sometimes there are oscillations, but I'm not sure how to judge them. (small osciallations (twitches) vs. bigger wobbles)  They're like in between.  I also get them when descending.

    Which parameters do I need to adjust in what way?


    Last question:

    Which parameters need to be tuned in what way (up or down) in general for a AP setup?

    There might be typical adjustments for smoother AP flight. (I know parameters need to be adjusted to different setups and payloads, but just in general)


    I really need help on tuning.  It really is not that easy, even when everything is explained in the Wiki pages.


    Thank in advance!

  • Moderator

    I have been getting a violent twitch on the roll of my Tricopter, it only happens when I am very slightly touching the sticks in order to hover, if I let go it doesnt happen and if I am flying it doesn`t happen? I thought it may be the dynamic gain on the Stab D parameter and have changed it several times and whilst it seems to be less violent it still happens?

    In fact a few days ago it flipped several times and into the deck for no apparent reason? I was just hovering after probably ten minutes of auto mode and some hard flying. Has only flipped the once with months of the same settings and hasn`t done it since?

    Any ideas would be welcome?

  • I have a question about Simple Mode.

    Last week I had a "hard landing" because I kind of lost orientation in Simple Mode, de copter was not reacting like I thought it would react.

    Only now I realized other multicopter systems use 2 different kind of Simple Modes, see picture below.


    What kind of Simple Mode does AC use?  "In Course lock" or "In Home lock"? Or can you actually choose in MP?

    I always thought that pulling the stick back would bring it back home, no matter what direction the copter is in.  It didn't, it reacted in a different way resulting in a hard landing. 

  • Hi all!

    Don´t be afraid, I will soon stop writing about my testflights here.Watch instead videos by Marco, Chris, Chris...

    But I am proud of my progresses!



  • The Maidenflight of my 3DR Hexa...

    PID = standard... just stab P --> 4.2 --> 4.1 --> 4.0

    Wind is a huge problem... the Hexa shake really much...

    Standard PID Settings dont work for me ;-((

    Code 2.5.5.

    Standard Parts (850KV motors)

    4s Lipo


  • Developer

    Images from Google Earth of my results with U-Blox GPS unit prototype:

    Hi all!
    Just for comparation with the images posted here by Chris (MTK GPS) this is my results with U-Blox GPS unit, judge yourself.
    The first image is the Loiter of my latest video, the other one two AUTO mission (in the same flight) with 5 waypoint and autoland at the end.
    In both test the wind is 8<->10 MPH, the autolanding at the end of this two mission has a maximum error of 4 meters from the point stated.
    Chris has conducted the tests with more wind, tomorrow I will try the same mission with both the gps unit.
    It's time to leave MTK if you want more accurate results (imho).

    Bests, Marco

    Loiter with U-Blox GPS
    Auto Waypoint

    Two AUTO mission with U-Blox GPS

  • Hi,

    For the past few days my log is not working anymore. When I try to pull the log it will shown the bellow:

    ArduCopter V2.5.5] logs logs enabled:  ATTITUDE_MED GPS PM CTUN NTUN CMD

    96 logs

    Log -1791,    start 1,   end 1

    Log -1790,    start 1,   end 1


    ys negative, and there is no informations.

    My hardware is APM2. I tried erase logs, erase eeprom, reset factory default, upload new firmware, upload fw using arduino. Tried latest code from GIT with new dataflash erase method, pul the dataflash and put it back.

    My hexa flew well, it just I need the log to help me with analyze my copter.

    Any idea what else I should do?

This reply was deleted.


Shivchand Jaysaval liked Shivchand Jaysaval's profile
Aug 25